1. Field of the Invention
The present invention generally relates to tape drives and, more particularly, to the winding of tape around reels within a tape drive.
2. Relevant Background
Tape drives have been widely employed in industry for over thirty years due to their ability to store large amounts of data on a relatively small and inexpensive removable format. Typically, tape drives use a storage tape that is wound between a pair of tape reels as data is transferred to or from the tape media via a read/write tape head assembly. In one arrangement, one of the reels (e.g., the “take-up” reel) is part of the tape drive while the other reel (e.g., the “cartridge” or “supply” reel) is part of a removable cartridge. Upon insertion of the cartridge into the tape drive, the storage tape on the cartridge reel must be coupled to the take-up reel of the tape drive (e.g., via respective leaders). After coupling, the tape is unwound from the cartridge reel, moved past the tape head assembly and wound onto the take-up reel via a drive motor. Next, the tape is unwound from the take-up reel, moved past the tape head assembly and wound onto the cartridge. Subsequently, the storage tape must be uncoupled from the take-up reel, prior to removing the cartridge from the tape drive. In another arrangement, both reels are part of a cassette which is inserted into a tape drive and driven by a drive motor.
To increase the storage density and reduce the access time of magnetic tapes, a popular trend is towards multi-head, multi-channel fixed head structures with narrowed recording gaps and data track widths so that many linear data tracks may be manipulated on a tape medium of a predetermined width (e.g., such as one-half inch width tape) passing by the head structures at increasingly faster rates of speed. However, various factors work against the ability of present systems to achieve such increased storage densities and reduced access times. As an example, “axial” run out or lateral motion of the tape as the tape moves past the tape head assembly can generate lateral registration differences or errors between the tape head assembly and the data tracks contained on the tape, thus inhibiting such increased storage densities and reduced data access times. As another example, “radial” run out refers to tension variations in the tape that negatively affect tape drive operations.